并非总是DNS问题。
It's not always DNS

原始链接: https://notes.pault.ag/its-not-always-dns/

作者提出了一条新的经验法则:如果即使在脑海中将“DNS”替换为“将名称映射到IP的键值存储”后,问题仍然存在,那么DNS就不是根本原因。 虽然“总是DNS的问题”这种说法很常见,但过度依赖它会阻碍有效的故障排除。DNS故障通常是*症状*,而不是核心问题。像IP连接失败或意外记录删除这样的问题源于潜在问题——有缺陷的自动化、网络问题——这些问题无论*如何*分发名称到IP的映射都存在。 作者认为,责怪DNS会分散对真正运营风险的识别,并鼓励肤浅的分析。*确实*存在需要解决的合法DNS特定问题,但将每个网络问题都归咎于DNS是一种肤浅且可能有害的做法。我们应该努力获得更细致的理解和更好的诊断。

## “并非总是DNS” - Hacker News 讨论总结 一个 Hacker News 帖子,源于一篇因足球转播法律命令在西班牙被屏蔽的博客,引发了人们对“总是DNS”这个技术笑话的讨论。虽然 DNS 问题是网络问题的常见原因,但讨论很快扩展到承认多种潜在原因。 用户指出审查(特别是西班牙当局屏蔽博客的行为)、BGP 问题,甚至更广泛的系统性问题,如配置错误和复杂的分布式系统,都是常见的故障来源。 许多评论强调,“DNS”梗并非指协议本身不可靠,而是它中心地位使其成为常见的故障点。 对话还深入探讨了 DNSSEC 部署的复杂性、简单系统设计的重要性,以及操作系统(如 Linux 的顺序 DNS 服务器列表)中经常被忽视的默认配置,这些配置可能会加剧问题。 最终,该帖子强调,虽然 DNS 通常是首先检查的地方,但彻底调查至关重要,将所有问题都归咎于 DNS 是一种过于简单的做法。
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原文

I’ve written down a new rule (no name, sorry) that I’ll be repeating to myself and those around me. “If you can replace ‘DNS’ with ‘key value store mapping a name to an ip’ and it still makes sense, it was not, in fact, DNS.” Feel free to repeat it along with me.

Sure, the “It’s always DNS” meme is funny the first few hundred times you see it – but what’s less funny is when critical thinking ends because a DNS query is involved. DNS failures are often the first observable problem because it’s one of the first things that needs to be done. DNS is fairly complicated, implementation-dependent, and at times – frustrating to debug – but it is not the operational hazard it’s made out to be. It’s at best a shallow take, and at worst actively holding teams back from understanding their true operational risks.

IP connectivity failures between a host and the rest of the network is not a reason to blame DNS. This would happen no matter how you distribute the updated name to IP mappings. Wiping out all the records during the course of operations due to an automation bug is not a reason to blame DNS. This, too, would happen no matter how you distribute the name to IP mappings. Something made the choice to delete all the mappings, and it did what you asked it to do

There’s plenty of annoying DNS specific sharp edges to blame when things do go wrong (like 8.8.8.8 and 1.1.1.1 disagreeing about resolving a domain because of DNSSEC, or since we’re on the topic, a DNSSEC rollout bricking prod for hours) for us to be cracking jokes anytime a program makes a DNS request.

We can do better.

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